Sweetpotato sirup



ti sired. Thus,

Patented Aug. 9, 1938 UNITED STATES PATENT OFFICE SWEET-POTATO SIRUP Howard s. Paine, Chevy Chase, Me, in Elias Yanovsky, Washington, D. 0.; dedicated to the use of the People of the United States of erlca l lo Drawing. Application Serial No. 153,1

1 Claim.

I(Granted under the m of March amended April 39,

. merit to, us of any royalty thereon.

We hereby dedicate the invention herein described to the free use of the People or the United iii Btates of America to take eil'ect on the granting of a patent to us.

it has been the practice among many brewers to add sugar or sugar solutions (sirups) tobeer wort before fermenting it for production of beer.

1 Bugar or sugar solutions used in this way as a brewing adjunct increase the yield oil beer, make W i i hie certain economies oi operation, and also sometimes impart certain desirable qualities to the ed been. Amongthe sugars contained t in thevarious brewlngadjuncts which have been used may be mentioned corn sugar (dextrose), invert sugar, sucrose, maltose and mixtures of these are. Some of the slrups and dry adiuncts contain also variable proportions of. dexuri' trins relatively small amounts of noni s bstances, such as ash constituents, proteins,

0pc of the disadvantages of such straps or mixtures coing principally of sugars is that, al-

so though they supply a considerable proportion oiv alcohol which is required in brewing beer, they are not sumciently flexible in composition to proride any required proportion of fermentable and non-fermentable constituents which may bedeunder some conditions in brewing beer a higher proportion of non-fermentable con-e stituents to fermentable constituents may be desired, and under all the various conditions of brewing a considerable range in proportion of in iermentable to non-fermentable constituents may 1 be desired. 1 1

V We have prepared a sirup which is'very suitable as a brewing adjunct from the above and other standpolnts. Sweet potatoes are known to 45 be very rich in carbohydrates, especially starch.

When sweet potates are ground and mixed with water and subjected to the action of a suitable concentration of acid, andalso to heat, the starch is converted into sugars and'dextrins and 90% 50 or more of the dry matter, of sweetpotatoes may betransformed into; soluble substances, which thus insuring aremain in solution in the sirup, high yieldof sirup per bushel of potatoes. Heating is conduct. preferably under pressure. By- 65 drochloric, sulphuric and other acids-may be m, 12, 1937, as

(Cl. 9H0) 8, 1883, as 1928; 370 Q. G. 751) used as hydrolytic agents but hydrochloric acidis preferred. After the necessary conversion is accomplished, the resulting liquid material, which contains suspended fiber and other insoluble con- I stituents, is filtered and a suitable proportion of sodium carbonate is added for the purpose of adlusting the liquid to the pH desired. The liquid is then treated with suitable decolorizingcarbon, and after filtration irom same, is boiled down to the desired concentration of solids. By

regulating the time andtemperature oi heating, the pressure and the concentration of acid, it is possible to adjust the ratio of ferm'entable sugars to non-fermentable solids within widellrnits.

It has usually been rmarded as impracticable to produce a satisfactory sirup bydirect acid hy drolysis of unpuriiled raw material such as whole sweetpctatoes, including the skin. it has customary to purify such raw materials in.

the extraction of starch from corn for production of glucose by acid hydrolysis or as an alterna vtive to use malt or other diastatic agent as a converting agent, as in the action of stilt on various grains. However, it has been found that by carefully controlling the conditions of hydrolysis there can be obtained an extract which is clear and of satisiactory color and which, after treatment with suitable decolorizing carbonand concentration, yields a sirup oil permanent clarity and of satisfactory color and flavor.

In attempts which have been made previously to produce a slrup from sweetpotatoes by using malt as a converting agent, there was obtained a pasty mass which, on account 0! the high proportion of insoluble or. unconverted material, re.- quired considerable manipulation in order to filter oi! the liquid portion. Also, because of the Nah P p rtion of unconverted material the yield of 'sirup per bushel of sweetpot'atoes was lowiabout 1.35 gallons per bushel of potatoes). Onthe other hand, the material obtained as a result of acid hydrolysis of sweetpotatoes (lnjusted within a wide range, give the necessary body" or unfermented extract to the finished beer. It is also feasible to mixthis sweetpotato sirup with another sirup such as one containing principally sucrose or sucrose and invert sugar (derived .irom sugarcane) so as to produce a Imixed sirup suitable for use as a brewing adjunct. In this way, a still greater range in the proportion of iermentable to non-fermentable constituents can be attained. Flavor is of importance in making such mixtures and it has been found that a satisfactory flavor is obtained when sweetpotato sirup prepared by acid hydrolysis is mixed with sirups or other liquid productsiderived from sugarcane) which contain essentially sucrose and/or invert sugar.

A typical example of the method of producing sweetpotato sirup by .acid hydrolysis is as follows: Ground, washed sweetpotatoes (including skins) are mixed with an equal weight of water and concentrated hydrochloric acid is added in proportion of two grams of acid to one pound of sweetpotatoes. However, any strong acid, such as sulphuric or nitric acid may be substituted for the concentrated hydrochloric acid named. In practice, the sweet potatoes may be washed in any suitable type of continuous potato washer and then ground in a hammer mill. The mixture is heated under pressure at 125 C. for 3% hours. The liquid extract is then filtered 01!, the filtrate is adjusted to required pH (usually about 5.0 pH) by addition of sodium carbonate and is then treated with suitable -decolorizing carbon for removal of color. Alter filtration from the carbon, the extract is concentrated to a sirup of to percent solids content. One sirup of 80 percent solids content prepared in this way contained 45 percent of iermentabie sugars and 35 percent of non-termentable solids. By varying the conditions of hydrolysis, the percentage 01 iermentable sugars can be materially increased through conversion of dextrins.

It should be understood that we do not limit ourselves to the above conditions of temperature,

time and concentration of acid but, on the confiltrate to the action of an alkali until it is adjusted to substantially 5.0 pH, thence adding a decoloriaing carbon, thence removing the carbon, and thence concentrating the remaining extract to a sirup content ranging from '10 to 80% solids.

. HOWARD 8. PAINE.

ELIAS YANOVSKY. 

